The SitePoint Forums have moved.

You can now find them here.
This forum is now closed to new posts, but you can browse existing content.
You can find out more information about the move and how to open a new account (if necessary) here.
If you get stuck you can get support by emailing forums@sitepoint.com

If this is your first visit, be sure to
check out the FAQ by clicking the
link above. You may have to register
before you can post: click the register link above to proceed. To start viewing messages,
select the forum that you want to visit from the selection below.

@oddz: I don't want to bother you anymore. This will be my last post on this topic, I need to find another way for learning this without having to make 3423423 posts. :s I realise that, and I'm really sorry. You explanations however, have been precious for starting on this OOP thing.

The script returns no errors. However, all the data inserted on the db table is NULL. I don't know why.

If it does then your problem is with the query. If it doesn't then the problem is outside this method.

Also, take a look at this this thread for the proper way to handle errors using prepared statements. Especially, throwing exceptions which will help you bug and error fix your code.

What does the create statement for the DOG table look like? The problem could be your leaving out a required field. In which case the prepare method would fail and if you were using proper error handling could easily identify by throwing an exception when execute or prepare fail.